[GR2017]

In my area the current temperatures are -20 to -25 degrees Celsius. Running the engine for 10-20 mins is ok but I would rather get into a warm vehicle than not. Running for just 20 mins warms the engine fine but 30 mins would allow it to be much more comfortable.

Not sure I would ever let a cold engine idle for more than a few seconds. The oil flow is just too low to adequately provide proper lubrication. I'm nearing 70, but I can still handle a few minutes in a cold cabin just fine.